The OSI model and the TCP/IP model

The OSI model and the TCP/IP model
9.1.6 This page provides a comparison of the OSI model and the TCP/IP model.

The OSI and TCP/IP models have many similarities:

• Both have layers.
• Both have application layers, though they include different services.
• Both have comparable transport and network layers.
• Both use packet-switched instead of circuit-switched technology.
• Networking professionals need to know both models.

Here are some differences of the OSI and TCP/IP models:

• TCP/IP combines the OSI application, presentation, and session layers into its application layer.
• TCP/IP combines the OSI data link and physical layers into its network access layer.
• TCP/IP appears simpler because it has fewer layers.
• When the TCP/IP transport layer uses UDP it does not provide reliable delivery of packets. The transport layer in the OSI model always does.

The Internet was developed based on the standards of the TCP/IP protocols. The TCP/IP model gains credibility because of its protocols. The OSI model is not generally used to build networks. The OSI model is used as a guide to help students understand the communication process.

The Interactive Media Activity will help students understand the differences between the TCP/IP and OSI reference models.

The next page examines the basic architecture of the Internet.

Comments

OSI layers / Peer-to-peer communications / TCP/IP model

OSI layers 2.3.4 This page discusses the seven layers of the OSI model. The OSI reference model is a framework that is used to understand how information travels throughout a network. The OSI reference model explains how packets travel through the various layers to another device on a network, even if the sender and destination have different types of network media. In the OSI reference model, there are seven numbered layers, each of which illustrates a particular network function. - Dividing the network into seven layers provides the following advantages: • It breaks network communication into smaller, more manageable parts. • It standardizes network components to allow multiple vendor development and support. • It allows different types of network hardware and software to communicate with each other. • It prevents changes in one layer from affecting other layers. • It divides network communication into smaller parts to make learning it easier to understand. In the foll...

Advantages and disadvantages of link-state routing

Advantages and disadvantages of link-state routing 2.1.5 This page lists the advantages and disadvantages of link-state routing protocols. The following are advantages of link-state routing protocols: Link-state protocols use cost metrics to choose paths through the network. The cost metric reflects the capacity of the links on those paths. Link-state protocols use triggered updates and LSA floods to immediately report changes in the network topology to all routers in the network. This leads to fast convergence times. Each router has a complete and synchronized picture of the network. Therefore, it is very difficult for routing loops to occur. Routers use the latest information to make the best routing decisions. The link-state database sizes can be minimized with careful network design. This leads to smaller Dijkstra calculations and faster convergence. Every router, at the very least, maps the topology of it...

Ports for services

Ports for services 10.2.2 Services running on hosts must have a port number assigned to them so communication can occur. A remote host attempting to connect to a service expects that service to use specific transport layer protocols and ports. Some ports, which are defined in RFC 1700, are known as the well-known ports. These ports are reserved in both TCP and UDP. These well-known ports define applications that run above the transport layer protocols. For example, a server that runs FTP will use ports 20 and 21 to forward TCP connections from clients to its FTP application. This allows the server to determine which service a client requests. TCP and UDP use port numbers to determine the correct service to which requests are forwarded. The next page will discuss ports in greater detail.

CCNA :) Be a Good Network Administrator

Search This Blog